Напольная акустика — Verity Audio Sarastro IIS

Verity Audio, the Quebec City manufacturer, builds the Sarastro IIS as a three-way tower. It belongs to Verity's eXR (Extended Range) line alongside the larger Lohengrin IIS, a series aimed at high efficiency, wide bandwidth and high dynamic capability, and it succeeds the original Sarastro. Although it is a full-range design, it resembles a monitor mounted on a matching stand, because its woofer faces the rear and no driver is visible on the lower section.

Key specs that matter

The Sarastro IIS combines Verity's own aluminium-foil ribbon tweeter, a 150mm (6-inch) midrange and a 280mm (11-inch) woofer with a 100mm (4-inch) voice-coil former. The woofer hands over to the midrange at 150Hz with a first-order (6dB/octave) slope, and a third-order filter separates the midrange from the tweeter at 6.5kHz. Bandwidth is 20Hz to 60kHz and sensitivity is 93dB at 2.83V/1m, with nominal impedance of 8 ohms. Amplifiers from about 7W upward can drive it. Each speaker measures 34.8 x 50.5 x 127.5cm and stands on a constrained-layer Floor Isolation Platform with adjustable feet.

Engineering and use context

The ribbon tweeter is a true ribbon, not a planar-magnetic design - a thin aluminium foil that is both diaphragm and conductor, suspended in a magnetic field. Verity began assembling its own ribbons by hand in Canada from European parts after supply problems with its previous American source, and the same tweeter is used in the Lohengrin and Monsalvat. A ribbon has very low impedance, so it is driven through a matching transformer, which is part of what allows the speaker's high sensitivity. The midrange and woofer are made to Verity's specifications by Audio Technology in Denmark. The woofer fires to the rear, as in most Verity speakers, from a cabinet that widens toward the back to accommodate it; this, together with sides that are not parallel, prevents standing waves forming inside. The rear bass-reflex port is custom-made from aluminium for Verity after noise problems were found with standard ports. The crossover uses special film capacitors made for Verity by a French specialist, and the gold-plated soft-copper terminals have been used by the company almost since its founding.

Pairing

Its efficiency and benign load let the Sarastro IIS work with low-power single-ended tube amplifiers as well as powerful solid-state amplifiers. Because the woofer faces backward, its distance from the rear wall strongly shapes bass output.

Alternatives

Verity Audio's own Lohengrin IIS is the larger eXR model, designed for large rooms with even higher sensitivity.